Table 2-12 On-Chip Emulation Port Signals - Motorola DSP56009 User Manual

Signal Descriptions
On-Chip Emulation (OnCE
2.10 ON-CHIP EMULATION (OnCE
There are four signals associated with the OnCE port controller and its serial
interface.
Signal Signal
Name Type
DSI Input
OS0 Output
2-22
TM
) Port

Table 2-12 On-Chip Emulation Port Signals

State
during
Reset
Output, Debug Serial Input (DSI)—The DSI signal is the
Driven signal through which serial data or commands are
Low provided to the OnCE port controller. The data
received on the DSI signal will be recognized only
when the DSP has entered the Debug mode of
operation. Data must have valid TTL logic levels
before the serial clock falling edge. Data is always
shifted into the OnCE port Most Significant Bit (MSB)
first.
Operating Status 0 (OS0)—When the DSP is not in
the Debug mode, the OS0 signal provides
information about the DSP status if it is an output
and used in conjunction with the OS1 signal. When
switching from output to input, the signal is
tri-stated.
Note: If the OnCE port is in use, an external
DSP56009 User's Manual
TM
) PORT
Signal Description
pull-down resistor should be attached to the
DSI/OS0 signal. If the OnCE port is not in use,
the resistor is not required.
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